export const createYears = () => {
    const years = []
    for(let i = 1900; i <= 2050;i++){
        years.push(i)
    }
    return years
}

export const createMonths = () => {
    const months = []
    for(let i = 1;i<=12;i++){
        months.push(i)
    }
    return months
}

export const getCurrentDate = () => {
    const date = new Date()

    return {
        year:date.getFullYear(),
        month:date.getMonth() + 1,
        date:date.getDate(),
    }
}

export const initList = (year,month) => {
    const list = []

    //1.计算选中的年月的1号星期几
    const firstDate = new Date(year,month - 1 ,1)
    let day = firstDate.getDay()//0-6
    if(day === 0){
        day = 7
    }

    //2.填充上个月
    //2.1 计算上个月的最后一天
    const lastMonthLastDate = new Date(year,month - 1, 0 )
    const an = lastMonthLastDate.getDate()
    //2.2上个月的总天数 
    const n = day - 1 
    const a0 = an - n + 1
    for (let i = a0;i <= an;i++){
        list.push({type:'last',date:i})
    }

    //3.填充本月
    const monthLastDate = new Date(year,month,0)
    //3.1本月的最后一天
    const bn = monthLastDate.getDate()
    for(let i = 1;i <= bn;i++){
        list.push({type:'this',date:i})
    }

    //4.填充下个月
    const cn = 42 - n - bn 
    for(let i = 1;i <= cn ; i++){
        list.push({type:'next',date:i})
    }

    return list
}